Axially damped hydraulic mount assembly

ABSTRACT

An example mount assembly includes a first chamber, at least partially defined by a first elastomeric element and a second chamber, at least partially defined by a second elastomeric element. The assembly also includes an inertia track having a central opening defining an axis. The inertia track defines a serpentine passage in fluid communication with the first chamber and the second chamber. The inertia track is moveable along the axis relative to the first elastomeric element and the second elastomeric element.

REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No. 12/865,602 filed Nov. 15, 2010, which claims priority to PCT Application No. PCT/US2009/033199 filed Feb. 5, 2009, which claims priority to U.S. Provisional Application No. 61/026,291 filed Feb. 5, 2008.

BACKGROUND OF THE DISCLOSURE

This disclosure relates to a mount assembly or damper, and particularly a mount assembly that damps vibrations imposed on the assembly in a load bearing environment, including a fluid effect damping that is a combination of frequency dependent resonant damping and broadband viscous damping.

Assemblies that damp vibrations and relative movement between components are well known. Many of these arrangements use an elastomer or natural rubber material disposed between first and housing portions that are secured to first and second vehicle components. It is desirable to limit vibration from the first component to the second component, for example, between a first component such as an automotive frame and a second component such as an engine. For example, an engine mount assembly includes a first housing portion mounted to the frame and a second housing portion secured to the engine and a material such as an elastomer or rubber interposed between the first and second housing portions that damps the vibrations.

When a component in a system is excited at its natural frequency, it can begin vibrating at high amplitudes. These high amplitude vibrations can be transferred from the origin of the excitation through a conventional mount to the side of the system where vibrations are not desirable. An axially damped hydraulic mount can be tuned to the natural frequency of the system and can reduce the transfer of vibrations from one side of the system to the other.

Other axially damped hydraulic mounts are known in the art. Moreover, it is also known to use a true double pumping hydraulic mount in which a hydraulic fluid is selectively conveyed between first (upper) and second (lower) chambers that are interconnected by an elongated path (inertia track). However, these types of hydraulic mounts have some functional limitations because of the need to secure the hydraulic mount via the housing to the surrounding environment.

It is also desirable to use the mount as a load bearing mount, or in combination with a typical shear style body mount in a rebound application, or an engine mount, or suspension mount application. Further, if used in such a combination, undue complexity in the assembly and sealing should also be avoided.

SUMMARY OF THE DISCLOSURE

A hydromount assembly includes first and second chambers separated by an inertia track having a passage that communicates with the chambers. An opening through a central portion of the inertia track is dimensioned to receive an associated fastener therethrough.

A hollow shaft extends through the first and second chambers and the inertia track, such that axial movement of the shaft results in axial movement of the inertia track to selectively pump fluid from one of the first and second fluid chambers to the other of the fluid chambers.

The inertia track is secured about an outer perimeter portion to an elastomeric material allowing the inertia track to selectively move in response to movement of the shaft that extends through the opening.

The inertia track preferably includes first and second portions separated along a plane perpendicular to an axis of the central portion opening.

The inertia track is secured about an outer perimeter portion to an elastomeric material allowing the inertia track to selectively move in response to movement of a shaft extending through the opening.

First and second, or first, second and third elastomeric elements have the same or different conformations or are formed from the same or a different material than one another.

A housing is received around the first and second fluid chambers and the inertia track, and a portion of the housing is crimped to compress inner perimeter portions of the inertia track and create a fluid seal.

An alternate sealing method comprises forming the inertia track from two stamped metal pieces and using the outer metal of the center molded component to crimp the upper and lower molded components.

A primary benefit of the disclosure relates to mounting through the center of the hydromount to significantly increase the functionality of the damper.

Another benefit resides in using the inertia track as a plunger that actuates fluids between the first and second fluid chambers to create a frequency dependent fluid effect damping.

Ease of assembly and a simplified manner of sealing the components together is also provided by the present disclosure.

An example mount assembly includes a first chamber, at least partially defined by a first elastomeric element and a second chamber, at least partially defined by a second elastomeric element. The assembly also includes an inertia track having a central opening defining an axis. The inertia track defines a serpentine passage in fluid communication with the first chamber and the second chamber. The inertia track is moveable along the axis relative to the first elastomeric element and the second elastomeric element.

An example mount assembly includes a first chamber, at least partially defined by a first elastomeric element and a second chamber, at least partially defined by a second elastomeric element. The assembly also includes an inertia track having a central opening defining an axis. The inertia track defines at least one passage in fluid communication with the first chamber and the second chamber. The inertia track is moveable along the axis relative to the first elastomeric element and the second elastomeric element. The assembly includes a hollow tube that seals against an axial end of the inertia track on a second chamber side.

An example mount assembly includes a first chamber, at least partially defined by a first elastomeric element and a second chamber, at least partially defined by a second elastomeric element. The assembly also includes an inertia track having a central opening defining an axis. The inertia track defines at least one passage in fluid communication with the first chamber and the second chamber. The inertia track is moveable along the axis between the first chamber and the second chamber. The assembly includes a shaft defining a shoulder that abuts a first axial end of the inertia track and a hollow tube that seals against a second axial end of the inertia track.

Still other features and benefits will be found in the following detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exploded view of a three piece hydraulic body mount assembly.

FIGS. 2 and 3 are perspective views of the assembled hydraulic body mount assembly of FIG. 1.

FIGS. 4 and 5 are exploded and installed views of the hydraulic mount assembly of FIGS. 1-3 in a shear style body mount design.

FIG. 6 is a longitudinal cross-sectional view of the double pumping hydraulic damper or hydromount assembly.

FIG. 7 is a longitudinal cross-sectional view of the three-piece hydraulic body mount assembly.

FIG. 8 is a perspective view of a center-fastened double pumping hydromount assembly.

FIG. 9 is a longitudinal cross-sectional view of the hydromount assembly of FIG. 8.

FIG. 10 is a perspective view of another embodiment of a hydraulic body mount assembly.

FIG. 11 is an exploded view of the mount assembly of FIG. 10.

FIG. 12 is a longitudinal cross-sectional view of the mount assembly of FIG. 10.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning first to FIGS. 1-3, a mount assembly or damper 100 is illustrated. A preferred embodiment of a mount assembly 100 includes a load bearing body mount 102, a hydraulic damper 104, and a travel restricting washer 106. The assembly 100 allows for a fastener such as a bolt (not shown) to pass through the center of the hydraulic damper, and in this case the body mount, while still creating damping in the axial direction. More particularly, the load bearing body mount 102 includes an upper, first component such as bearing plate 110 spaced from a lower, second component or mounting plate 112. The load bearing body mount further includes a damping member (sometimes referred to as a main rubber element or MRE) such as an elastomeric material or natural rubber 114 that is secured at opposite ends to the first component 110 and the second component 112, respectively. For example, the damping member may be mold bonded to the plates 110, 112 in a manner well know in the art. The mounting plate preferably includes first and second flanges 120, 122 that extend laterally outward and include openings that receive fasteners 124, 126, respectively. As perhaps best evident in FIG. 7, the body mount further includes a central hollow rigid sleeve 130 that extends through the elastomeric member and is mold bonded along an external surface thereof with the elastomeric member. The rigid components of the mount (e.g., plates 110, 112 and sleeve 130) are preferably formed from any suitably hard material (composite, aluminum, steel, etc.), and any suitably performing compliant substance (generally referred to as an elastomer which includes an elastomer, natural rubber, etc.) can be used in the compliant portion of the system. The plate 110 and the sleeve 130 are preferably formed from separate metal components that are subsequently joined (e.g., welded) together for ease of assembly, although it will be understood that the sleeve and the plates 110, 112 may be formed from the same type of rigid material (for example, metal) or from a rigid composite material. Further, the bearing plate 110 and the sleeve 130 could be a deep drawn integral or homogeneous structural arrangement, however, the least expensive arrangement is to form the bearing plate and sleeve as separate components, and subsequently join the individual components together.

The hydraulic damper or hydromount 104 is illustrated in FIGS. 1-5 and more particular details are shown in the cross-sectional views of FIGS. 6 and 7. The hydraulic damper is a “double pumper” design where hydraulic fluid is forced back and forth by the pumping action of opposing elements, i.e., upper and lower fluid chambers 140, 142. The concept of a double pumping hydraulic mount is known in the art; however, what makes this preferred arrangement unique is that the hydraulic damper 104 allows for a fastener such as a mounting bolt (not shown) to extend through the hydraulic damper without adversely impacting the functional operation of the hydraulic damper portion of the assembly. Particularly, in the illustrated preferred embodiment, an upper or first main rubber element (MRE) 144 forms a first or upper end of the upper fluid chamber 140 and similarly a lower or second main rubber element 146 for a first or lower end of the lower fluid chamber 142. The first and second fluid chambers are separated by an inertia track 150 which is an elongated, preferably serpentine interconnecting passage that ads in damping vibrations between the upper and lower ends of the hydromount. For example, the inertia track is typically a stationary component that has a winding path shown here as being formed from first and second stamped components 152, 154 that abut against one another, and together form a continuous passage 156. The passage 156 communicates with the upper fluid chamber 140 at one end and with the lower fluid chamber 142 at the other end. Vibrations are damped by the inertia track in a manner well known in the art and in addition this structural arrangement provides for viscous fluid damping where the fluid flow through the passage is limited due to the cross-sectional dimension of the passage and thereby provides the viscous fluid damping between the first and second fluid chambers. In the present arrangement, the inertia track 150 is a movable component that spans between the first and second fluid chambers and is resiliently mounted about an outer peripheral portion with elastomer sidewall 158. The sidewall 158 may be formed at least partially from a rigid component such as a generally cylindrical rigid element or sidewall 160, and likewise portions of the end 144 of the first fluid chamber 140 and the end 146 of the second fluid chamber 142 may include rigid components 144 a, 146 a. Preferably, however, the remainders of the first and second fluid chambers are formed from an elastomeric/rubber material so that the ends 144, 146 may selectively move or deflect and cause a pumping action of the fluid through the inertia track passage and between the first and second chambers.

Further, a rigid inner hollow shaft 170 extends through the hydromount and is adapted to receive a fastener (not shown) therethrough. As seen in FIG. 7, the shaft 170 in the hydromount preferably aligns with the sleeve 130 in the body mount in order to easily assemble these damping components together. An opening through shaft is shown as preferably having a tapered conformation that decreases in size as the shaft extends axially from the first fluid chamber to the second fluid chamber. A first shoulder 172 is dimensioned to abuttingly engage and align the shaft with the sleeve at the upper end of the hydromount. A second shoulder 174 is dimensioned to abuttingly and sealingly engage the inertia track, namely a first or upper surface thereof, at a radial inner location. As a result of molding the inertia track in an elastomeric material, the elastomeric material at this inner radial location serves as a seal between the shaft second shoulder 174 and the inertia track 150. Similarly, a rigid hollow tube 180 is received over the other end of the shaft so that a first end 182 of the tube seals against a second or underside surface of the inertia track at the inner radial location. In this manner, the first and second fluid chambers are sealed from one another along the inner radial region as a result of the shaft second shoulder and the tube 180. A second end 184 abuts against the washer 106.

The hydromount further includes a rigid, metal housing (sometimes referred to as a can or shell) 190 that encompasses the separately molded first and second main rubber elements 144, 146 disposed at axial opposite ends of the first and second fluid chambers 140, 142, and the separately molded inertia track. Preferably, a first or upper end 192 of the housing sealingly engages the first main rubber element 144 and by deforming or crimping the first end 192 radially inward, the hydromount is sealed at the first/upper end. That is, the housing first end seals against an outer peripheral region of the first main rubber element 144. An inner peripheral region of the first main rubber element, that preferably includes rigid insert 144 a, is sealed or mold bonded to a radial outer surface of the shaft 170 to form a first subassembly of the hydromount assembly. The second main rubber element 146, which also preferably includes the rigid insert 146, is sealed (preferably by mold bonding) to an outer peripheral surface of the tube 180 to form a second subassembly of the hydromount assembly. A second or lower end 194 of the housing receives the second subassembly or second main rubber element therein. Rigid sidewall 160 is connected to an outer periphery of the inertia track via an elastomeric material that is preferably mold bonded thereto to form a third subassembly. The elastomeric material preferably extends along the entire height or interior surface of the sidewall 160 so that when assembled in the housing, the sidewall forms outer peripheral portions of the first and second fluid chambers and axially spans and seals against the first main rubber element 144 at a first or upper end to the second main rubber element 146 at a second or lower end.

To assemble the hydromount, the sidewall 160 is advantageously located in a mold with the first and second components 152, 154 of the inertia track to form one of the molded subassemblies. The first main rubber element is molded to an external surface of the shaft to form another of the molded subassemblies. Likewise, the second main rubber element is molded to an external surface of the tube to form still another of the molded subassemblies. The three subassemblies are introduced into the housing one atop another and the second shoulder abuttingly seals against the upper, inner peripheral portion of the inertia track and the tube is pressed over the shaft to compress and seal along a lower, inner peripheral portion of the inertia track. A single deformation or crimp is formed in the housing at the first end 192 with the three subassemblies received in position in the housing to compress the housing against the first main rubber element, and likewise compress the three subassemblies together.

As illustrated in FIGS. 8 and 9, an alternative hydromount assembly 210 that a first or upper molded component 212 and a second or lower molded component 214, that form a first/upper portion of a first fluid chamber 216 and a second/lower portion of a second fluid chamber 218, respectively. The fluid chambers are in fluid communication via an inertia track 220 that includes first and second stamped metal inertia track portions 222, 224, for example, that abut one another to form an elongated inertia track passage 226 that communicates with the first fluid chamber at one end and the second fluid chamber at the other end. A third or center molded component 230 is radially spaced and interconnected with the inertia track portions 222, 224 by an annular elastomeric or rubber member 232 that is preferably secured (e.g., mold bonded) along an inner periphery to the metal components and along an outer periphery to the third molded component 230 to form one of the subassemblies. A second molded subassembly includes shaft 234 molded along an outer surface thereof to an inner perimeter portion of a second annular elastomeric/rubber member 236, and an outer perimeter portion of the second rubber element 236 is mold bonded to the molded component 212 to form a second subassembly. A third annular elastomeric/rubber member 238 is molded along an outer perimeter portion with the inner surface of the second molded component 214 and also molded along an inner perimeter portion with a tube 250. Further, the shaft includes a shoulder 240 that abuttingly engages and seals with an inner diameter region of the inertia track. Likewise, a sleeve 250 is press fit over the shaft 240 and the sleeve abuttingly engages an underside of the inertia track to seal thereagainst. The center molded component includes flanges at opposite axial ends that are crimped or deformed into locking engagement with outer peripheries of the first and second molded components to hold the three subassemblies together in a single assembly.

FIGS. 10-12 have similar structures and functions to the previously described embodiments. Again, separately molded subassemblies are compressed together in a housing, although in this arrangement, the body mount is integrated into the first main rubber element. More specifically, body mount 300 includes an upper, first component or bearing plate 302 spaced from a lower, second component of mounting plate 304. The plates 302, 304 are spaced by a first main rubber element 306 which also serves to form an upper surface of the first fluid chamber. The first main rubber element is molded to the two plates 302, 304, and also to shaft 308 extending downwardly from a first or lower surface of the plate 302. If desired, rigid ring member or tube 310 is molded in the rubber element 306 along a lower, inner perimeter portion of the first rubber element.

The second subassembly includes a three-piece inertia track assembly which extends the length of the passage almost two-fold in comparison to the passages of the prior embodiments by using inner and outer radial passages formed in a first or upper portion 320, a second or lower portion 322, and a separating plate 324 that has an opening that connects passage portions in the upper inertia track portion 320 with the passage portions in the lower inertia track portion 322. Sidewall 326 has an inner surface that is molded to the inertia track assembly by an elastomeric member that preferably encompasses the three-part inertia track assembly.

The third subassembly includes a second main rubber element 330 that preferably includes a rigid insert 332 along an outer radial portion and is molded to a tube 334 along an inner radial portion. The third subassembly in conjunction with the inertia track portion forms the second or lower fluid chamber.

Housing 340 receives the third subassembly, then the inertia track subassembly, and then the first subassembly through an open top 342. The housing further includes a radially extending flange 344 that abuts with a lower or underside surface of the mounting plate 304. A crimping member 350 then joins the flange 344 and plate 304 together to press the first, second and third subassemblies together in sealed relation in the housing.

Independent axial dynamic tuning, using the fluid effect of the mount, as deemed necessary by the system in which it is installed can be provided while providing mounting through the center of the shaft, and with the inertia track mounted to the shaft. In these designs, the shaft with through fastener or through bolt is allowed to move relative to the outer housing/third molded component. The inertia track therefore becomes the physical member or plunger that actuates the fluid between the upper and lower chambers thereby creating frequency dependent fluid effect damping. An inertial track also pumps resulting in additional viscous damping. The combination of viscous damping and a tuned track (inertia track) to create simultaneous broad-band and resonating fluid damping is believed to be unique, and substantially different than known hydromounts.

These multi-piece designs of the assembly allow a great range of rubber tuning as the upper load bearing mount can use a different rubber hardness and/or compound than that of the lower hydraulic damper. For example, butyl rubber could be used in the load bearing body mount and natural rubber could be used in the hydraulic damper, or vice versa.

A fastener through the center of the mount significantly increases the functionality of the damper. Although these mounts can be used as load bearing mounts, one of the unique characteristics is that the hydromounts could be used in conjunction with a typical shear style body mount in a rebound application. Further applications for these designs as either a load bearing mount, or as an addition to a load bearing mount, are engine mount or suspension mount applications. These designs also reduce the assembly and sealing complexity that would be expected of center fastening, double pumping, hydraulic mounts.

As noted above, the axially damped hydraulic mount uses the inertia track as the fluid actuating plunger and allows a fastener to pass through the center of the mount. This axially damped hydraulic mount uses a configuration that allows for the same triaxial static rates and travels as a conventional elastomeric mount. The present disclosure improves the durability of a hydraulic actuated mount by separating the load bearing portion of the mount from the damping (fluid filled) portion of the mount.

The axially damped, double pumping, hydraulic mount of the present disclosure can be used in applications where higher levels of damping than conventional elastomeric mounts are capable of are required. The embodiments of the present disclosure can be used in applications where the only means of fastening the mount to the system in which it is being used is through the center of the mount. The mount can be used in packaging situations where other mounts would not otherwise fit.

Additional tuning flexibility is achieved because the three legs or main rubber elements (MRE) can be tuned independently of each other. It will be further understood by those skilled in the art that the shape or conformation of the mount need not be round but can also adopt other shapes, e.g., rectangular, square, etc.

This hydraulic mount design works well in shear style body mount designs because it allows the hydraulic damping portion of the body mount to be located under the “pedestal” or frame side bracket (see FIGS. 4 and 5 where the hydromount 104 is located beneath the pedestal). This allows for considerable design flexibility for the frame and body structures. It will be appreciated, however, that the hydraulic portion of the mount can also be installed below the vehicle frame bracket.

The damper of this disclosure also allows for independent axial dynamic tuning, using the fluid effect of the mount as deemed necessary by the system into which it is installed.

Another key feature of the present disclosure is the ease of assembly and unique sealing method for a double pumping hydraulic mount. The damper portion of the mount is sealed with a single crimp, which compresses the seal on the inner molded components. A tube is pressed over the inner shaft to compress the seals at the inertia track. An alternate sealing method comprises forming the inertia track from two stamped metal pieces and using the outer metal of the center molded component to crimp the upper and lower molded components. A tube press-fit over shaft seals the inertia track.

The invention has been described with reference to the preferred embodiment. Modifications and alterations will occur to others upon reading and understanding this specification. It is intended to include all such modifications and alterations in so far as they come within the scope of the appended claims or the equivalents thereof. 

1. A mount assembly comprising: a first chamber, at least partially defined by a first elastomeric element; a second chamber, at least partially defined by a second elastomeric element; and an inertia track including a central opening defining an axis, the inertia track defining a serpentine passage in fluid communication with the first chamber and the second chamber, wherein the inertia track is moveable along the axis relative to the first elastomeric element and the second elastomeric element.
 2. The assembly of claim 1, wherein the inertia track is located between the first chamber and the second chamber.
 3. The assembly of claim 1, wherein the serpentine passage includes a first opening to the first chamber that is axially offset from a second opening to the second chamber.
 4. The assembly of claim 1, wherein the first elastomeric element and the second elastomeric element are made of equivalent compositions of material.
 5. The mount assembly of claim 1, wherein a third elastomeric element is located between a housing and the inertia track and separates the first chamber and the second chamber.
 6. The mount assembly of claim 1, wherein the inertia track is moveable such that the inertia track actuates fluid between the first chamber and the second chamber and moves relative to a housing, wherein the housing is radially outward of the central opening.
 7. The mount assembly of claim 1, wherein the inertia track includes a first distinct track piece that includes a first portion of the serpentine passage and a second distinct track piece that includes a second portion of the serpentine passage, wherein the first distinct piece and the second distinct piece are attached together such that the first portion and the second portion align to form the serpentine passage.
 8. The mount assembly of claim 7, wherein the first distinct track piece and the second distinct track piece are metal.
 9. A mount assembly comprising: a first chamber, at least partially defined by a first elastomeric element; a second chamber, at least partially defined by a second elastomeric element; an inertia track including a central opening defining an axis and defining at least one passage in fluid communication with the first chamber and the second chamber, wherein the inertia track is moveable along the axis relative to the first elastomeric element and the second elastomeric element; and a hollow tube that seals against an axial end of the inertia track on a second chamber side.
 10. The assembly of claim 9, further comprising a shaft that defines a shoulder that abuts the inertia track.
 11. The assembly of claim 10, wherein the shaft seals the first chamber from an inner radial region of the opening.
 12. The assembly of claim 10, wherein the shaft is hollow and extends through the first chamber.
 13. The assembly of claim 10, wherein movement of the inertia track is responsive to movement of the shaft.
 14. The assembly of claim 9, wherein the at least one passage is a serpentine passage.
 15. A mount assembly: a first chamber, at least partially defined by a first elastomeric element; a second chamber, at least partially defined by a second elastomeric element; an inertia track including a central opening defining an axis and defining at least one passage in fluid communication with the first chamber and the second chamber, wherein the inertia track is moveable along the axis between the first chamber and the second chamber; a shaft defining a shoulder that abuts a first axial end of the inertia track; and a hollow tube that seals against a second axial end of the inertia track.
 16. The assembly of claim 15, wherein the shaft seals the first chamber from the opening.
 17. The assembly of claim 15, wherein the shaft is hollow and extends through the first chamber.
 18. The assembly of claim 15, wherein movement of the inertia track is responsive to movement of the shaft.
 19. The assembly of claim 15, wherein the shoulder is generally perpendicular to the axis.
 20. The assembly of claim 19, wherein a portion of the inertia track abutting the shoulder is generally perpendicular to the axis.
 21. The assembly of claim 15, wherein the tube overlaps a portion of the shaft.
 22. The assembly of claim 15, wherein the second elastomeric element seals the hollow tube against the second axial end of the inertia track.
 23. The assembly of claim 15, further comprising a third elastomeric element is located between a housing and the inertia track and separates the first chamber and the second chamber. 